"I'm concerned about highway safety. I am concerned about jobs," Teamsters head James P. Hoffa said in an interview at Teamsters headquarters, according to Automotive News. "I am concerned we are moving too fast in a very, very strategic area that we have to make sure we are doing it right because lives are involved."

Though the loss of truck-driving jobs is certainly a cause for concern for a union representing truck drivers, the safety concerns reflect those that others have voiced about the relaxed regulations for self-driving cars. It's one thing for a two-ton car without manual controls to lose control and cause a crash. It's quite another for an 80,000-pound 18-wheeler, which could cause far more damage.

The Senate Commerce Committee is scheduled to hold a hearing about self-driving trucks on Wednesday. Teamsters general secretary-treasurer Ken Hall will testify that allowing autonomous commercial trucks as "fundamentally different, and potentially more calamitous than those facing passenger cars." Troy Clarke, CEO of truck manufacturer Navistar International Corp. and head of the American Trucking Association, will also testify.

Companies like Uber, Tesla, and TuSimple are already gearing up to produce autonomous trucks that would be immune to fatigue—and, potentially, lead to the removal of daily limits on how many hours truck operators are allowed to be on the road. Profits and productivity could skyrocket by not having to employ a human driver with human weaknesses and limitations. But Tesla has already been reprimanded for not employing enough safeguards in their self-driving technology. And up to 3 million commercial trucking jobs could be lost if human drivers are replaced.